@H. Malcom WalkerNot addressing specifically the story in question, but contests in general: I "vote" in contests, but I "score" other stories.
In general, when I start reading a story, I reach a decision about whether I like it or not. If I don't, I usually say, "I am not into the same kinks as the target audience." Then I stop reading it, and don't give it a score at all.
If I do give a story a score, it's because I read it to the end, so I give it a score of at least "OK." Also, at that point, I score matching my feeling to the word scores ("Excellent," "Good," etc.). The effect is that the average score I give is probably around 7.3.
On the other hand, for a contest, I try to read as much as I can of all the entries, and then I give a score to all of them - even the ones I disliked so much I couldn't finish them. Those scores are then relative to the pool. To maximize the weight of my opinion, I have to spread the scores as widely as possible. If there are two stories, I will give one a 10, the other a 0. In this case, I think I gave my favorite a 10, my second choice a 9, and I certainly spread the scores on the other stories all the way down to 0. The effect was that the average score I gave on the contest was probably slightly less than 5.
Supposing that other voters do something similar (if less calculated) the scores in contests will naturally end up being lower than for regular stories (at least, on average).
I repeat my original comment, though: this is not an opinion about the specific story by H. Malcolm Walker. I do not recall what score I gave that story, and it isn't relevant to my point. My point is that there is a reason why scores in contests may be lower than in general.